The invention relates to a high-voltage power breaker having two arcing contact pieces which are separated from one another when disconnected and between which an arc is struck, possibly in an arcing area filled with a quenching gas, with a quenching gas which has been heated by the arc flowing out from the constriction point of an insulating nozzle which surrounds the arcing area, through at least one outlet flow channel, which has a number of areas which the quenching gas passes through successively.
DE-U 93 14 779.1 and DE-A 29 47 957 describe such a high-voltage power breaker.
In the known power breakers, an arc is in each case struck between two arcing contact pieces during disconnection, is blown by a quenching gas, and is in consequence intended to be quenched and prevented from restriking. A heating area is often provided, in which quenching gas which has been heated up by the arc is stored at high pressure until the next current zero crossing of the current to be switched, in order then to flow back to the arcing area when the pressure drops in the arcing area, and to cool the quenching gas there. In order to achieve effective cooling, the quenching gas must then be able to flow through an outlet flow channel into an expansion area.
In order to prevent the inner walls of an encapsulating enclosure of a power breaker from being damaged or contaminated by contaminated hot quenching gases, the quenching gas is cooled and deionized in a cooling device. Such cooling devices have, for example, what are referred to as mesh coolers in the form of perforated plates and metal meshes, in which the interaction surface area for the hot quenching gas is extremely large.
The cooling of the quenching gas also prevents ionized quenching gas from flowing into the switching path between the arcing contact pieces when another switching process takes place shortly afterwards.
It has been found that, for an optimum switching response, a certain build-up of the quenching gas is required in the outlet flow channel, although an excessively large build-up, for example due to a dense metal mesh through which the quenching gas has to flow, can impede arc quenching.
In one embodiment of the invention, there is a high-voltage power breaker. The power breaker includes, for example, two arcing contact pieces which are separated from one another when disconnected and between which an arc is struck in an arcing area filled with a quenching gas which has been heated by the arc, an insulating nozzle surrounding the arcing area, the insulating nozzle including a constriction point from which the quenching gas flows in an outlet flow direction through at least one outlet flow channel having a number of areas which the quenching gas passes through successively, wherein a first area faces the constriction point of the nozzle and has a specific flow resistance which is less than that of the constriction point, the first area in the outlet flow direction of the quenching gas is followed by at least a second area, a third area and a fourth area, in which a specific flow resistance of the second area and of the fourth area, respectively, is greater than a specific flow resistance of an immediately preceding area in the outlet flow direction, and the specific flow resistance of the third area is less than that of the second area.
In another aspect of the invention, the fourth area, whose specific flow resistance is greater than that of the preceding area, is formed by a radial deflection apparatus to quench gas flow.
In another aspect of the invention, the second and fourth areas, which have a higher specific flow resistance than their respective preceding areas, each have cross-sectional constrictions in the outlet flow channel.
In still another aspect of the invention, the cross-sectional constrictions are in the form of nozzles.
In another aspect of the invention, at least one of the areas having a higher specific flow resistance than that of the respective preceding area is in the form of a check valve.
In another aspect of the invention, each check valve has a linearly moving plate which may close an opening.
In yet another aspect of the invention, at least one of the check valves has at least one closure flap which can pivot about a hinge.
In another aspect of the invention, at least one of the areas having a higher specific flow resistance than that of the respective preceding area is in the form of a body provided with a plurality of through-flow openings.
In another aspect of the invention, at least one of the areas having a higher specific flow resistance than that of the respective preceding area has a flow damping device.
In still another aspect of the invention, the outlet flow channel extends from the nozzle constriction point to a drive side, and at least one of the areas having a higher specific flow resistance than that of the respective preceding area follows, in the outlet flow direction, a drive-side vacuum interrupter to which one of the arcing contact pieces is fitted.
In another embodiment of the invention, there is a method of designing a high-voltage power breaker. The method includes, for example, providing two arcing contact pieces which are separated from one another when disconnected and between which an arc is struck in an arcing area filled with a quenching gas which has been heated by the arc, providing an insulating nozzle surrounding the arcing area, the insulating nozzle including a constriction point from which the quenching gas flows in an outlet flow direction through at least one outlet flow channel having a number of areas which the quenching gas passes through successively, wherein a first area faces the constriction point of the nozzle and has a specific flow resistance which is less than that of the constriction point, the first area in the outlet flow direction of the quenching gas is followed by at least a second area, a third area and a fourth area, in which a specific flow resistance of the second area and of the fourth area, respectively, is greater than a specific flow resistance of an immediately preceding area in the outlet flow direction, and the specific flow resistance of the third area is less than that of the second area.
In another aspect of the invention, the method includes forming the fourth area, whose specific flow resistance is greater than that of the preceding area, by a radial deflection apparatus to quench gas flow.
In another aspect of the invention, the method includes forming respective cross-sectional constrictions, in the outlet flow channel, in the second and fourth areas, which have a higher specific flow resistance than their respective preceding areas.
In yet another aspect of the invention, the method includes forming the cross-sectional constrictions in the form of nozzles.
In another aspect of the invention, the method includes forming at least one of the areas having a higher specific flow resistance than that of the respective preceding area in the form of a check valve.
In another aspect of the invention, the method includes providing a linearly moving plate, which may close an opening, for each check valve.
In still another aspect of the invention, the method includes providing at least one closure flap, which can pivot about a hinge, in at least one of the check valves.
In another aspect of the invention, the method includes forming at least one of the areas having a higher specific flow resistance than that of the respective preceding area in the form of a body provided with a plurality of through-flow openings.
In another aspect of the invention, the method includes providing a flow damping device in at least one of the areas having a higher specific flow resistance than that of the respective preceding area.
In yet another aspect of the invention, the method includes extending the outlet flow channel from the nozzle constriction point to a drive side, and providing a drive-side vacuum interrupter to which one of the arcing contact pieces is fitted at least one of the areas having a higher specific flow resistance than that of the respective preceding area follows, in the outlet flow direction.